Why is the world so cold when it’s closest to the sun in January?

This is definitely a question that would be asked by someone in the Northern Hemisphere, since January in the Southern Hemisphere is definitely warm! From a global perspective, when the Earth is farther away from the sun in its orbit, the average temperature does increase by about 4°Fahrenheit (2.3°Celsius), even though the sunlight falling on Earth at aphelion is about 7 percent less intense than at perihelion.

So why is it warmer when we are farther away from OUf star? The main reason is the uneven distribution of the continents and oceans around the globe. The Northern Hemisphere contains more land, while the Southern Hemisphere has more ocean. During July (at aphelion), the northern half of our planet tilts toward the sun, heating up the land, which warms up easier than the oceans. During January, it’s harder for the sun to heat the oceans, resulting in cooler average global temperatures, even though the Earth is closer to the sun.

But there is another cause for warm temperatures in the north when the Earth is at aphelion: the duration of summers in the two hemispheres. According to Kepler’s second law, planets move more slowly at aphelion than they do at perihelion. Thus, the Northern Hemisphere’s summer is 2 to 3 days longer than the Southern Hemisphere’s summer, giving the sun more time to bake the northern continents.